Mechanics that I know have built both auto's and manuals. They say an auto is easier to build, but everything must be clean and in the right order. Take your time, and when in doubt, pull out the micrometer and the pictures. Never be afraid to post pictures and ask questions. I believe that Mike L will talk you through just about any problem that you may have.
Never done one, but want to try. Just can't do without my truck and don't have a garage or enclosed area that I could do it in.
I am considering taking a week off and driving out to see Mike for a tranny build on mine. Might even ask if he will let me watch just for my own knowledge.